#include <QCoreApplication>
#include <iostream>
#include<cmath>
#define PI 3.14159265
using namespace std;

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    double L, R, S;
      cin >> L;
      R = L/(2 * PI);
      M_PI;
      S = PI * R*R;
      cout << "R -> " << R << "\nS -> " << S << endl;

    return a.exec();
}
